posts_nav_link(); not working

Hi Everyone,

I am completely new to WordPress and I am learning how to develop my own themes.

I have attempted to create pagination with the posts on my font page but it just displays the same posts on each page.

Here is my code:

<?php query_posts("posts_per_page=5"); ?>
		<?php if (have_posts()) : while (have_posts()) : the_post(); ?>

		<a class="posttitle" href="<?php the_permalink() ?>"><?php the_title(); ?></a>

		<p><?php the_excerpt(); ?></p>

		<?php endwhile; ?>

		<div id="previousandnext"><p><?php posts_nav_link(); ?></p></div>

		<?php else : ?>

		<h2>Not Found</h2>

		<?php endif; ?>

Does anyone have any idea what I am doing wrong?

Thanks in advance 🙂